Any suggestions on how this happened? It's only one season old, just got unit back from winterization and it was still out of the heater.. Should I buy a new one service rep is telling me it's only a drain plug?!?!

If anyone tells you the anode rod is JUST a drain plug on a Suburban brand water heater, they need to educate themselves more.

Sacrificial anode rod protects your water heater tank from corrosion by attracting corrosive elements in water, so they attack the anode rod rather than your water heater tank interior.
Simply remove the anode rod from the tank and inspect it every three months. If it is mostly eaten away, replace it with a new one to extend the life of the tank.

To answer your original question, as others have stated you still have much life left in that one pictured. How long an anode rod last depends a lot on the content of the water in the tank, which is different in different parts of the country, municipalities, etc.

You had concerns about it being brittle near the bolt head. There is a metal rod that goes thru the entire length as you can see in the usage chart at 100% usage, so it's not going to break.

Any suggestions on how this happened? It's only one season old, just got unit back from winterization and it was still out of the heater.. Should I buy a new one service rep is telling me it's only a drain plug?!?!

"It's only a drain plug?" - what else has your service rep told you?

It's your water heater anode rod that's attached to a drain plug for removal,inspection and replacement when necessary.

I'm often amused when people ask how could their water heater anode rod could deteriorate so fast for the following reasons:

1. There is no hard and fast rule regarding how fast these deteriorate - it depends on the mineral content of the water that is going into the water heater. If it's "soft" water,the rod will last longer that one in a water heater that "hard" water is used in.

2. As the rod deteriorates it's only doing it's intended function - its role is to "sacrifice" itself so the harmful minerals in the water attach it and not the water heater tank itself.

As stated - a chart showing the various stages of deterioration of these rods is posted and should be your guide in determining when you should replace the rod.

Any suggestions on how this happened? It's only one season old, just got unit back from winterization and it was still out of the heater.. Should I buy a new one service rep is telling me it's only a drain plug?!?!

Mine looked a lot worse than that after one season yours is good for at least another season